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Query: “If grid is grouped by datetime column, sorting other columns does not work any more.”
We have validated the reported issue by preparing a sample as per your suggestion. To replicate the reported issue we have grouped the Date column first. Then tried to sort the other column. We are able to reproduce the reported behavior at our end.
By default once a column is grouped it will be sorted and will be moved to hidden state. Now sorting the other column is like MultiSorting approach. In your case, first column will be sorted and grouped based on the original dataSource, when we sort any other column the sorting will be applied based on the first column which is grouped and sorted. So sometimes it might look like sorting is not applied. But it depends upon the values from the data source.
Consider (In attached sample) we have used two column, OrderDate and CustomerID columns. First we have grouped the OrderDate Column. Now OrderDate column will be grouped and Ascending order (sort) will be applied to it. Now click on CustomerID column header to sort the column. Since already one column is sort and grouped, now sorting will be applied to already sorted groups. So it might looks like sorting is not performed. But it depends upon the dataSource value.
To explain more clearly we have prepared a sample which contains same date value in more that 5 records. Refer the below sample for your reference
Note: In above sample you will be able to sort other column when date column grouped.
If you are still facing the issue, kindly get back to us with more details.